Don’t have an outlet? Charge your smartphone with a candle

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Battery life hasn’t caught up with the power and sophistication of our mobile devices — something our sister site ExtremeTech regularly laments. This often leads to people purchasing a secondary charger to carry around just in case, as well as everyone becoming hyper-aware of where outlets are located. However, what if your phone is about to die and you’re waiting on an important call? You run to the nearest coffee shop, but alas, the outlets are all in use, and everyone using them looks too focused on their work to give up their slot. Thankfully, Instructables user David Johansson has a perfect solution: a DIY thermoelectric generator that can charge your device.

The device resembles something of a Bunsen burner with a heat sink on top, plugged into a USB cable. Johansson is able to generate enough power to charge a smartphone thanks to a Peltier element. When used as a cooler, the Peltier effect will transfer heat from one side of an element to another; for instance, when used as a heat sink, the heat will be transfered from the processor side of the element to the other side, which is attached to the aforementioned heat sink. A Peltier element can be used as generator by heating up one side of the element to a greater temperature than the other side, which creates a difference in voltage, otherwise known as the Seebeck effect.

Johansson’s generator is capable of creating voltage by being heated with a gas or alcohol burner, or even tea lights. So, maybe it’s not a perfect phone-charging solution, but it’s pretty neat.

Portable thermoelectric generators exist, but Johansson’s DIY solution is one of — if not the — smallest capable of charging a phone, making it easy enough to lug around. It’s actually a decent way to charge your phone if you, for example, want to go camping, but can’t quite leave all of advanced technology behind.

If you’re of the skilled type of human ilk, you can build your own using Johansson’s very detailed set of step-by-step instructions. If you aren’t, you can check out the instructions anyway and feel a little sad, but be mightily impressed by Johansson’s work.